Curvilinear-axis focusing and aberration theory of wide electron beams forcombined immersion magnetic-electrostatic lens systems

Curvilinear-axis Gaussian electron optical properties and aberration charac teristics of wide electron beams for combined immersion magnetic-electrosta tic lenses are studied. Based on general wide beam and curvilinear-axis the ory, paraxial trajectory equations in local orthogonal coordinates are obta ined, and all of the second-order curvilinear-axis aberration coefficients are derived using a symbolic manipulation software Mathematica. The present paper lays a theoretical groundwork for further studies on curvilinear-axi s focusing and aberration theory for the combined immersion magnetic-electr ostatic lenses.